Floating caisson for repairing floating dry-dock bottoms.



No. 808,638. PATENTED JAN. 2, 1906. A. 0. CUNNINGHAM. FLOATING GAISSONFOR REPAIRING FLOATING DRY DOCK BOTTOMS.

APPLICATION FILED MAE.10, 1905.

ANDREW C. CUNNINGHAM, OF ANNAPOLIS, MARYLAND.-

FLOATING CAISSON FOR REPAIRING FLOATING DRY-DOCK BOTTOIVIS.

Specification of Letters Patent.

Patented Jan. 2, 1906.

Application filed March 10, 1905. Serial No. 249,398.

To all 107710112, 710 nuty concern:

Be it known that 1, ANDREW O. CUNNING- HAM, a citizen of the UnitedStates, residing at Annapolis, Anne Arundel county, Maryland, haveinvented certain new and useful Improvements in Floating Caissons forHepairing Floating Dry-Dock Bottoms; and I do hereby declare thefollowing to be a full, clear, and exact description of the invention,such as will enable others skilled in the art to which it appertains tomake and use the same.

In order to repair the-bottom of a floating dry-dock, it has heretoforebeen necessary to dock the dock itself, either in a graying-dock or onanother floating dock, or else where the dock to be repaired was asectional dock it was necessary to dock the section needing repairs onthe other sections.

So far as I am aware there has heretofore been no way in which thebottom of a floating dry-dock could be repaired except by docking it inone or the other of the ways above described; and my present inventionhas for its object to provide means whereby access may be had underwater to the bottom of these docks in order that they may be repairedwithout the employment of divers and without the necessity of dockingthem.

To this end the invention consists in a movable under-water caissonconsisting of an open-topped working chamber having a bottom and closedon all sides, whichis adapted to be submerged to the depth required tofloat it under a dock, the caisson being also provided with means forexhausting the water from the working chamber, so that workmen may enterand work therein. The caisson has also a shaft extending above the waterdown which the workmen may pass into the working chamber, and preferablyit also has a supplemental flotation-chamber, which is separate from theworking chamber and whose functionis to control the depth of sub mersionof the caisson and to cause it to make a water-tight joint between theupper edge of the working chamber and the bottom of the dock. Theworking chamber is provided with means, such as an inlet-valve, topermit the entrance of water to sink the caisson to the depth determinedby the displacement of the flotation-chamber, and the flotation-chamberis also provided with means for admitting and exhausting water to andfrom it in order to enlarge or diminish its displacement for the purposeof regulating the depth of submersion of the working chamber.

The invention is illustrated in the accompanying drawings, wherein-Figure 1 is an end view of a floating drydock with my repair-caissonapplied thereto. Fig. 2 is a side elevation of the caisson detached.Fig. 3 is a plan view of the caisson. Figs. 4 and 5 are verticalsections of the same, taken, respectively, on the lines 4 4 and 5 5 ofFig. 3; and Fig. 6 is a detail view showing the packing around the upperedge of the working chamber of the caisson.

Referring to the views, a wherever occur ring denotes the dock, whichmay be of any construction and is here shown diagrammatically only. Asillustrated in the drawings, it has a flat bottom; but though this isthe usual construction the bottom may be inclined or curved in anypreferred manner.

The caisson is indicated at I). It is an open-topped chamber having abottom and closed on all sides. It may be rectangular in shape, as shownin the drawings, or circular, or of any other shape, and the size,depth, and other dimensions will depend upon the requirements of use.This chamber constitutes a working chamber or room into which theworkmen may enter and in which they may work after the chamber has beensunk to the proper level and applied to the dock, as hereinafterdescribed. Around its upper edge the chamber has a flange c, on which issecured a packing-stripclof any suitable flexible material. As hereshown, this strip consists of a hollow tube having a rubber hose e onthe inside and a canvas cover f on the outside, with a filling g ofgreasy wool or cotton between the hose and cover. It is secured to theflange c in any suitable manner and is sufliciently elastic to make atight joint between the upper edge of the working chamber and the bottomof the dock when the caisson is adjusted to position. As best shown inFigs. 3 and 5, the working chamber is provided with a lateral offset 7L,and from this offset a shaft or stack 1' extends vertically to a heightsufficient to leave its upper end always above the water. This shaftcommunicates freely with the working chamber through the offset h and isfor the purpose of allowing the workmen to descend by a stairway j orother convenient means and enter the chamber after the caisson has beenadjusted to position and after the water has the shaft i.

been pumped therefrom, so as to permit them to work therein.

Fig. 1 illustrates the manner of using the caisson. Normally it floatsupon the surface of the water, and in order to apply it to the underside of a dock it must be sunk until its upper edge is below the bottomof the dock, when it may be moved about freely by guylines and pulledinto the required position under the dock. In order to sink the caisson,water is let into the working chamber 1) through an inlet-valve 70,which is controlled from above water by a rod Z, extending down Lettingthe water into the chamber through this valve will cause the caisson tosink to a level which will be determined by the displacement of asupplemental or flotation chamber m, which is preferably arranged withinthe working chamber and has a displacement capacity suflicient to floatthe caisson with its edge just above the waterline when the workingchamber 1) is filled with water. Water having been let into the workingchamber, as above described, and the caisson sunk until nearlysubmerged, it is further sunk by letting water into theflotation-chamber through a valve n, that is controlled from above by arod 0,until the entire caisson is lowered sufficiently to be hauled bythe guy-lines under the bottom of the dock, as shown in Fig. 1. It mustthen be secured to the dock-bottom, and this is effected by umping thewater out of the flotation-chamlder by means of a pump 39 through a pipeq, so as to lighten the displacement of this chamber and cause thecaisson to press upwardly against the bottom of the dock with the edgesof the working chamber around its open top compressing the packing dagainst the dock-bottom, so as to close the working chamber at the topand form a water-tight joint with the bottom of the dock. The caissonhaving thus been adjusted to position under the dock,it is of coursenecessary to pump the water out of the working chamber in order that theworkmen may enter and work therein. For this purpose a pump 7 isprovided, communicating by a pipe 8, extending down the shaft to nearthe bottom of the offset 72 which is preferably on a level with thefloor of the working chamber. Exhausting the water from the workingchamber not only provides a dry place for the men to work in, butgreatly diminishes the displacement of the caisson as a whole and causesit to press much more tightly against the bottom of the dock than themere emptying of the flotation-chamber would do.

It is not intended to limit the invention to any particular form ofworking chamber nor to any particular form or location of theflotation-chamber, nor, indeed, to any particular form, arrangement, orlocation of the passageway or entrance to the working chamber. The shafthere shown is a convenient and effective means for affording access tothe interior of this chamber and providing also for the entrance of airand light. Any other means, however, for permitting access to thechamber could be employed.

What I claim, and desire to secure, is

1. An under-water-floating caisson for repairing the bottoms of floatingdry-docks, the same comprising an open-topped working chamber having abottom and closed on all sides, said chamber being adapted to beentirely submerged and floated under the dock, and provided with meansfor exhausting the water therefrom, and having a shaft extending abovewater to permit workmen to enter the chamber after it is in place.

2. An underwaterfloating caisson for repairing the bottoms of floatingdry-docks, the same comprising an open-topped working chamber having abottom and closed on all sides, said chamber having a supplementalflotation-chamber and means for admitting and exhausting water from saidflotationchamber.

3. An underwaterfloating caisson for r e pairing the bottom of floatingdry-docks, the same comprising an open-topped working chamber having abottom and closed on all sides, a supplemental flotation chamber, meansfor admitting water to the flotationchamber to give the working chamberthe required submersion, means for exhausting the water from theflotation-chamber to cause the open top of the working chamber to fitwater-tight against the bottom of the dock, and means for exhausting thewater from the working chamber to permit the workmen to enter and worktherein.

In testimony whereof I affix my signature in presence of two witnesses.

ANDREW C. CUNNINGHAM.

Witnesses:

L. D. GAPAWAY, JAs. A. WALTON.

